<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>变量</title>
    <script>
        // 声明变量同时赋值为18  如果值是字母或者汉字，需要单引号括起来
        var age = 18
        // 控制台打印输出
        console.log(age)
    </script>
</head>
<body>
    
</body>
</html>